I have refinished a bunch of aluminum wheels, tho I have yet to tackle a Corvette wheel. I use aircraft aluminum stripper, seems to be commonly available at most body shop supply. I started with an Eastwood Wheel Buffing and Smoothing Kit, and finished with Mothers Aluminum Polish. It took some experimentation to figure out buff speed and pressure because I didn't have anybody to show me how, just read and figured it out on my own. First wheel I ever did took me all weekend. By the second set, I had it down to about two hours per wheel.
I appreciate this question because it made me research what would be correct finish for the C3 wheel and prompts some follow-up questions. Looking at several close-up pics of the c3 slotted aluminum wheels on digitalcorvettes.com, it
appears the slots were all originally painted and I can't tell from
pictures whether the surface was smooth or cast inside the slots. On some wheels I have done, the "slots" were natural sand-cast finish, and thus sandblasting with a medium media was perfect (after thickly masking the polished surfaces. Also, the wheels I have done have a distinct spun machine pattern and thus I was careful to buff in the direction of the pattern. Its hard to tell from the pictures if the Corvette wheels had any machine pattern originally or if they were all mirror smooth.